Understanding the mechanisms of bone formation and regeneration, should be the basis for much of what we do in orthopaedic surgery today. Since there has been a literal explosion in knowledge of cell control mechanisms centered on growth factors, membrane activation, matrix cell interaction, differentiation etc., it is crucial for us to take a renewed look at the bone regeneration process utilizing these latest findings and techniques. The Research Council of The American Academy of Orthopaedic Surgeons (AAOS) proposes an interdisciplinary conference/workshop to stimulate new research that will lead to a better understanding of these vital processes. The workshop will identify the biological and biophysical factors that contribute to normal and abnormal bone growth and repair with special attention directed toward growth factors, progenitor cells, biophysical environment and effects of operative intervention. The workshop will emphasize an interdisciplinary approach (biology, biochemistry, biophysics, molecular biology, embryology, morphology and ultrastructure, biomechanics, cell biology and physiology) to the complex processes that govern bone regeneration and maintenance. Specific areas of emphasis will include bone formation, normal and abnormal; bone repair and regeneration; bone remodeling; biosynthetic bone grafting; distraction osteogenesis; and fracture etiology, biomechanics and outcome. The format of the meeting will include presentations by invited participants of their previously submitted manuscripts combined with an in-depth discussion, followed by breakout sessions in which areas of critical concern (definition of gaps in knowledge, and future research directions) will be defined. As an additional stimulus to future research we also plan a publication summarizing the current state of knowledge and avenues for future investigation. A full summary of the proceedings and recommendations will be presented to NIAMSD. This workshop represents a continuum of a format established jointly by the NIH and AAOS to address critical areas of concern in musculoskeletal disease.